Abstract: Strengthening Referral Networks for Management of Hypertension Across the Health System Elevated blood pressure is the leading cause of global mortality and is increasingly prevalent in lower-middle- income countries (lower-MICs). Treatment and control of hypertension is an evidence-based and cost-effective strategy to reduce cardiovascular disease (CVD); however, rates of treatment and control of hypertension in lower-MICs are low. Strong referral networks for hypertension management are essential to ensure access to quality care as well as appropriate resource utilization. Patients with uncomplicated hypertension can be re- ferred to lower levels while patients with complicated hypertension requiring complex diagnostic and treatment strategies should be referred to higher levels. Referral adherence rates remain low, however, hindering effec- tive hypertension care. Contextual and culturally appropriate interventions are required to strengthen referral networks for hypertension control. Health information technology (HIT) and peer-based support strategies have shown potential in improving outcomes in communicable and non-communicable disease management. How- ever, their effectiveness in strengthening referral networks to improve hypertension control is relatively un- known. Therefore, the overall objective of this proposal is to utilize transdisciplinary implementation research, guided by the PRECEDE-PROCEED framework, to address the challenge of improving hypertension control in low-resource settings. We propose to test the hypothesis that referral networks strengthened by an integrated HIT and peer support intervention will be effective and cost-effective in improving hypertension control among patients in western Kenya. We further hypothesize that changes in referral network characteristics may medi- ate the impact of these interventions, and that baseline referral network characteristics may moderate the im- pact. Aim 1 is to conduct a needs and contextual assessment to evaluate factors that may impact integration of HIT and peer support in this setting, using a mixed-methods approach. We will then design a contextually and culturally appropriate intervention to strengthen referral networks for hypertension control. Aim 2 is to evaluate the effectiveness of the intervention among individuals with hypertension, by conducting a two-arm cluster ran- domized trial comparing usual care to an integrated HIT and peer support intervention to enhance referrals. The primary outcome measure will be one-year change in systolic blood pressure, and a key secondary out- come will be change in QRISK2 CVD risk score. We will also conduct a mediation analysis and a moderation analysis to evaluate the influence of referral network characteristics on outcomes. Aim 3 is to evaluate the cost-effectiveness of the intervention. The research will be accomplished by a transdisciplinary research team with diverse and complementary expertise, led by two Early Stage Principal Investigators. We aim to add to existing knowledge of innovative, scalable, and sustainable strategies to reduce CVD risk in hypertension and other chronic diseases among vulnerable populations in low-resource settings worldwide.